FILE - In this Tuesday Aug, 16, 2005 file photo an iceberg melts in Kulusuk, Greenland near the arctic circle. Scientists who are fine-tuning a landmark U.N. report on climate change are struggling to explain why global warming appears to have slowed down in the past 15 years even as greenhouse gas emissions keep rising. Leaked documents show there is widespread disagreement among governments over how to address the contentious issue in Sept. 23-26 stock-taking report by the Intergovernmental Panel on Climate Change. (AP Photo/John McConnico, File)

The Arctic Ocean

The Arctic is leading a race with few winners, warming twice as fast as the rest of the Earth. Loss of snow and ice, which reflect the sun's energy, is usually blamed for the Arctic temperature spike.

But a new study suggests the Arctic's cap of cold, layered air plays a more important role in boosting polar warming than does its shrinking ice and snow cover. A layer of shallow, stagnant air acts like a lid, concentrating heat near the surface, researchers report today (Feb. 2) in the journal Nature Geoscience. (LiveScience)